Water treatment apparatus and water treatment method

Abstract

A water treatment apparatus that can remove persistent organic materials more efficiently is provided. Water treatment apparatus has hypohalogenous acid addition means that adds hypohalogenous acid to water to be treated that contains organic materials; and ultraviolet ray radiating apparatus that is positioned downstream of hypohalogenous acid addition means and that radiates ultraviolet rays to the water to be treated to which the hypohalogenous acid has been added.

1 . A water treatment apparatus comprising:
 hypohalogenous acid addition means that adds hypohalogenous acid to water to be treated that contains organic materials; and   an ultraviolet ray radiating apparatus that is positioned downstream of the hypohalogenous acid addition means and that radiates ultraviolet rays to the water to be treated to which the hypohalogenous acid has been added.   
     
     
         2 . The water treatment apparatus according to  claim 1 , further comprising pH adjusting means that is positioned upstream of the ultraviolet ray radiating apparatus and that adjusts pH of the water to be treated to 3 or more and 8 or less. 
     
     
         3 . The water treatment apparatus according to  claim 1 , further comprising TOC analysis means that measures TOC of the water to be treated upstream of the hypohalogenous acid addition means, wherein the hypohalogenous acid addition means adds hypohalogenous acid having mass concentration that is at least 30 times the TOC that is measured by the TOC analysis means. 
     
     
         4 . The water treatment apparatus according to  claim 1 , wherein the organic materials contain urea,
 further comprising urea analysis means that measures concentration of urea in the water to be treated upstream of the hypohalogenous acid addition means, wherein the hypohalogenous acid addition means adds hypohalogenous acid having mass concentration that is at least 5 times the concentration of urea that is measured by the urea analysis means.   
     
     
         5 . The water treatment apparatus according to  claim 1 , wherein the hypohalogenous acid is hypobromous acid. 
     
     
         6 . The water treatment apparatus according to  claim 5 , wherein the hypohalogenous acid addition means includes means for supplying sodium bromide, means for supplying sodium hypochlorite, and means for mixing the sodium bromide and the sodium hypochlorite. 
     
     
         7 . The water treatment apparatus according to  claim 1 , further comprising an ion exchanger apparatus that is positioned downstream of the ultraviolet ray radiating apparatus. 
     
     
         8 . The water treatment apparatus according to  claim 1 , further comprising another ultraviolet ray radiating apparatus that is positioned downstream of the ultraviolet ray radiating apparatus. 
     
     
         9 . The water treatment apparatus according to  claim 1 , wherein the water to be treated contains anions, further comprising:
 hydrogen peroxide addition means that is positioned downstream of the ultraviolet ray radiating apparatus and that adds hydrogen peroxide to the water to be treated to which the ultraviolet rays are radiated;   anion removing means that is positioned downstream of the hydrogen peroxide addition means and that removes the anions from the water to be treated to which the hydrogen peroxide has been added; and   platinum group catalyst carriers that are positioned downstream of the anion removing means and that removes the hydrogen peroxide that is contained in the water to be treated from which the anions have been removed.   
     
     
         10 . The water treatment apparatus according to  claim 9 , wherein the anion removing means is anion exchangers, further comprising an ion exchanger tower in which the anion exchangers and the platinum group catalyst carriers are loaded. 
     
     
         11 . The water treatment apparatus according to  claim 10 , wherein the ion exchanger tower is a regenerative ion exchanger tower in which the anion exchangers, cation exchangers, and the platinum group catalysts are separately loaded, and wherein the anion exchangers and the platinum group catalyst carriers are loaded adjacent to each other. 
     
     
         12 . The water treatment apparatus according to  claim 9 , wherein the anion removing means is anion exchangers, further comprising:
 an ion exchanger tower in which the anion exchangers are loaded; and   a catalyst tower in which the platinum group catalyst carriers are loaded.   
     
     
         13 . The water treatment apparatus according to  claim 12 , wherein the ion exchanger tower is a regenerative dual-bed ion exchanger tower in which cation exchangers are further loaded. 
     
     
         14 . A water treatment method comprising:
 adding hypohalogenous acid to water to be treated that contains organic materials; and   radiating ultraviolet rays to the water to be treated to which the hypohalogenous acid has been added.   
     
     
         15 . The water treatment method according to  claim 14 , wherein the water to be treated contains anions, further comprising:
 adding hydrogen peroxide to water to be treated to which the ultraviolet rays are radiated;   removing the anions from the water to be treated to which the hydrogen peroxide has been added; and   removing the hydrogen peroxide by platinum group catalysts, wherein the hydrogen peroxide is contained in the water to be treated from which the anions have been removed.   
     
     
         16 . The water treatment method according to  claim 14 , wherein the organic materials contain urea.